Effects of UV‐filter Photostabilizers in the Photostability and Phototoxicity of Vitamin A Palmitate Combined with Avobenzone and Octyl Methoxycinnamate

Abstract

A challenge for cosmetic and dermatologic products is to develop new high‐performance and safer anti‐aging products based on new compounds to enhance the stability of retinyl palmitate combined with broad‐spectrum UV‐filters. Consequently, the aim of this work was to evaluate the effects of three often used avobenzone photostabilizers—ethylhexyl methoxycrylene (EHMCR), tris(tetramethylhydroxypiperidinol) citrate (TTMHP) and tris‐biphenyl triazine (TBPT)—on the photostability and phototoxicity of the combination of avobenzone (AVO), octyl methoxycinnamate (OMC) and retinyl palmitate (RP). The photostability studies were performed by the exposure of formulations to UVA radiation. The phototoxicity was evaluated by the 3T3 neutral red uptake phototoxic assay (OECD TG 432). The addition of EHMCR, TBPT, and TTMHP in the formulations, with/or without RP, improved the photostability of AVO and RP, but EHMCR was the most effective in stabilizing RP. In the phototoxicity assay, the combinations AVO‐OMC containing or not RP showed phototoxic potential. EHMCR and TTMHP reduced the phototoxicity of the combination AVO‐OMC, whereas EHMCR also decreased the phototoxicity of the combination containing RP. Therefore, EHMCR might be used to the photostabilization of formulations of AVO‐OMC with/or not RP, while TTMHP can be added to this photounstable UV‐filter combination.

Drug Delivery Strategies for Avobenzone: A Case Study of Photostabilization

“…As a result, EHMCR may be used to photostabilize AVOB-OMC formulations with or without RP, whereas TTMHP could be added to this photounstable UV-filter combination. The addition of EHMCR to this mixture increased the photostability of both compounds, resulting in a reduction in phototoxicity [ 85 ].…”

Assessment of the photoprotective potential and structural characterization of secondary metabolites of Antarctic fungus Arthrinium sp

“…Some UV lters available in the market present higher photo-instability than the fractions and isolated compound 6 of this study. Rangel and co-workers (2020), studied the photostability of some UV lters on the market and the results showed that benzophenone-3 presented approximately 30% of UV absorption reduction, and the broadspectrum UV lter avobenzone showed a considerable decrease (about 90% reduction) of UV absorption after exposure to UVA radiation (Rangel et al, 2020;Scarpin et al, 2021).…”

Sun protection, progress, myths, and inconsistencies (a proposal for the democratization of ISO 24443)

“…[11][12][13][14][15] Researchers have made different proposals to improve the performance of the filters to radiation exposure, such as nano and micro-encapsulation, ROS trappers and inhibitors, and synthesis of new molecules with improved photostability. [16][17][18][19][20][21][22][23][24] Several methods and irradiation sources have been used along the time to study the photostability of different molecules and formulations. ity of the UV filters, which is particularly feeble for the UVA.…”

“…Researchers have made different proposals to improve the performance of the filters to radiation exposure, such as nano and micro‐encapsulation, ROS trappers and inhibitors, and synthesis of new molecules with improved photostability 16–24 …”